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Real-time pollen data for Pittsburgh — updated daily.
Pittsburgh's Appalachian Plateau location provides access to one of the most diverse temperate deciduous forests in North America, producing an exceptionally varied tree pollen profile. Oak trees are the dominant allergen — red oak, white oak, and pin oak grow throughout Allegheny County's parks, residential neighborhoods, and the surrounding hillsides, releasing heavy pollen loads from April through May. Maple trees (red maple, sugar maple, and box elder) pollinate early in March and April, often before leaves emerge. Birch is a potent allergen that produces lightweight, highly reactive pollen in April and May. Ash trees pollinate in April. Elm begins as early as March. Hickory and walnut produce pollen in May. Sycamore trees line the river corridors of the Allegheny, Monongahela, and Ohio rivers, releasing both pollen and irritating seed fibers. Cottonwood and poplar trees grow along riverbanks and produce the visible cotton-like seed dispersal that fills the air in late spring. Pine trees contribute large quantities of visible yellow pollen in late spring, though pine pollen is less allergenic than hardwood species. The city's extensive park system — including Frick Park (644 acres), Schenley Park (456 acres), Highland Park, and Riverview Park — contains dense stands of mature deciduous trees that produce concentrated pollen. Pittsburgh's hilly topography means tree pollen produced on ridgetops can settle into valley neighborhoods where it concentrates in the still air.
Grass pollen season in Pittsburgh runs from late May through July, with peak counts typically in June. Timothy grass is the dominant grass allergen in western Pennsylvania, thriving in the temperate climate and producing highly allergenic pollen. Bluegrass (Kentucky bluegrass) is the standard residential lawn grass throughout Pittsburgh and its suburbs, pollinating from May through July. Orchard grass and ryegrass are common in parks, athletic fields, and maintained landscapes. Fescue contributes additional grass pollen. The city's neighborhood parks, athletic fields at schools, and the extensive lawn areas throughout residential neighborhoods all produce grass pollen during the warm months. Pittsburgh's numerous golf courses and the maintained grounds of institutions like the University of Pittsburgh, Carnegie Mellon University, and Chatham University add grass pollen sources. The river valleys can trap grass pollen during morning temperature inversions, preventing dispersal and creating concentrated pollen loads at ground level in low-lying neighborhoods. Unlike southern cities, Pittsburgh's grass pollen season is more compressed — roughly three months compared to seven in subtropical locations — but the peak intensity in June can match or exceed counts in warmer regions.
Ragweed is Pittsburgh's dominant fall allergen and one of the most significant contributors to seasonal allergy misery in western Pennsylvania. Ragweed season typically begins in mid-August and continues through the first hard frost, usually in late October. A single ragweed plant produces up to a billion pollen grains per season, and the lightweight pollen can travel over 100 miles on air currents. Ragweed grows prolifically in disturbed soils, vacant lots, railroad corridors, construction sites, and along the riverfronts. Pigweed (amaranth) and lamb's quarters colonize urban soils throughout the city. Dock and sorrel contribute fall pollen. Mugwort and nettle add seasonal triggers. Pittsburgh's industrial legacy has left numerous brownfield sites — former steel mills, railroad yards, and manufacturing facilities — where disturbed and contaminated soils support dense stands of pioneer weeds including ragweed. The Mon Valley industrial corridor, the Strip District's edges, and abandoned rail lines throughout the region provide ideal ragweed habitat. Pittsburgh's river valley geography concentrates weed pollen in the same terrain traps that hold industrial emissions, creating a fall allergy season where biological allergens and air pollution compound each other's respiratory effects.
Pittsburgh's allergen profile is uniquely shaped by the interaction between biological allergens and industrial air pollution. The three rivers (Allegheny, Monongahela, and Ohio) create elevated humidity along their corridors, promoting mold growth on riverbanks, floodplains, and in adjacent neighborhoods. Seasonal flooding — particularly along the Monongahela and in low-lying communities — produces mold blooms that can persist for weeks after waters recede. Alternaria, Cladosporium, Aspergillus, and Penicillium mold species are prevalent in Pittsburgh's air. Older housing stock throughout the city (many homes date to the early 1900s) is particularly susceptible to basement moisture, poor ventilation, and mold growth. Dust mites thrive in heated indoor environments during Pittsburgh's long winter months. Pet dander is a constant indoor trigger. But the factor that truly distinguishes Pittsburgh from other northeastern cities is air quality. Allegheny County has received failing grades from the American Lung Association for both particulate matter and ozone pollution for 20 consecutive years. Research has shown that children living near industrial pollution sources in Pittsburgh had 58 percent higher odds of developing asthma. Fine particulate matter (PM2.5) from the Clairton Coke Works, vehicle emissions, and industrial sources inflames airways independently, making allergic reactions to pollen and mold measurably more severe. Temperature inversions — where cold air is trapped beneath warm air in the river valleys — can hold both industrial pollution and biological allergens at ground level for days, creating some of the worst respiratory conditions in the eastern United States.
Severity: Low to Moderate
Winter provides Pittsburgh's most significant allergy relief as cold temperatures suppress pollen production and freezing conditions kill mold on outdoor surfaces. However, indoor allergens intensify as Pittsburghers spend extended time in heated homes with limited ventilation. Dust mites, pet dander, and indoor mold (especially in older homes with basement moisture issues) are the primary triggers. By late February, early tree pollination begins — elm and maple can release pollen during warm spells even before snow has fully melted. March brings the first measurable tree pollen as temperatures warm. Winter is also the season of temperature inversions, when cold air settles into the river valleys and traps industrial emissions at ground level. These inversions can last days and produce Air Quality Index readings that exceed healthy levels. In January and February 2026, the Allegheny County Health Department issued multiple health warnings for hydrogen sulfide and particulate matter in the Mon Valley region during prolonged inversions.
Severity: High to Severe
April through June is Pittsburgh's most intense allergy period. Oak, birch, maple, and ash trees produce overlapping pollen waves through April and May, with oak typically generating the highest counts. Pine pollen adds dramatic visual impact in May, coating outdoor surfaces in visible yellow dust. Late May through June brings the overlap of late tree pollen with surging grass pollen as Timothy grass, bluegrass, and orchard grass enter peak pollination. June typically has the highest combined pollen counts of the year. The three-river confluence creates circular air patterns that keep allergens circulating in the downtown area rather than dispersing. Morning fog in the river valleys traps pollen at ground level along riverfront trails and in low-lying neighborhoods. Pittsburgh's hills create pollen "pockets" — terrain features where allergen concentrations are significantly higher than in areas just a short distance away but at different elevations. Air quality begins improving as warmer temperatures reduce the frequency of temperature inversions, though ozone starts building on hot days.
Severity: Moderate to High
July sees declining grass pollen as the peak passes, but Pittsburgh's summer heat promotes ozone formation from industrial and vehicle emissions. Ground-level ozone irritates airways independently of biological allergens and can make pollen sensitivity worse. August brings the beginning of ragweed season — Pittsburgh's second major pollen peak of the year. By September, ragweed counts are at their highest, producing severe symptoms for the estimated 15 to 20 percent of the population sensitive to ragweed. Mold counts rise through summer as humidity increases along the river corridors and rain promotes growth on outdoor surfaces. The combination of ragweed, elevated mold, and summer ozone makes late August through September one of Pittsburgh's most challenging periods for respiratory health. Hurricane remnants occasionally bring heavy rainfall to western Pennsylvania in September, causing river flooding that promotes extensive mold growth in low-lying areas.
Severity: Moderate (October) declining to Low (December)
October brings declining ragweed pollen as overnight temperatures drop toward freezing. The first hard frost — typically in late October — definitively ends outdoor pollen season, providing the clear seasonal break that southern cities lack. Mold remains elevated through October as fallen leaves decompose in the damp autumn air. November marks the transition to indoor allergen season as Pittsburghers close windows and turn on heating systems, circulating dust, pet dander, and mold spores through aging ductwork. December's cold temperatures bring pollen relief but the return of temperature inversions that trap industrial emissions in the river valleys. The holiday season often coincides with poor air quality days when inversions hold pollution at ground level. For allergy sufferers, the October-through-February period is the best time to start or intensify treatment, building immune tolerance before the next spring pollen season arrives.
Pittsburgh sits at the confluence of the Allegheny and Monongahela rivers, which join to form the Ohio River at Point State Park. This geography — a city built in and around river valleys flanked by steep hills rising 300 to 400 feet above the water — is the single most important factor shaping Pittsburgh's allergy experience. The river valleys act as natural channels that funnel and concentrate airborne pollen. Morning fog and humidity in the valleys trap allergens at ground level, particularly along the riverfronts and in low-lying neighborhoods. Temperature inversions — where cold air settles into the valleys beneath warmer air above — create atmospheric lids that prevent both industrial pollution and biological allergens from dispersing. These inversions can last days during winter months, producing some of the worst air quality in the eastern United States. The hills surrounding the valleys create pollen "pockets" where allergen concentrations can be significantly higher than on ridgetops just a few hundred feet above. Mount Washington, Polish Hill, the South Side Slopes, and other hillside neighborhoods experience different allergen patterns than low-lying areas like the Strip District, Lawrenceville, or the North Shore. Understanding your neighborhood's elevation and proximity to the river corridors helps predict your specific allergen exposure.
Pittsburgh's transformation from the "City of Smoke" to a 21st-century technology and medical hub is one of America's great urban renewal stories. But the industrial legacy persists in ways that directly impact allergy sufferers. Allegheny County has received failing grades for air quality from the American Lung Association for 20 consecutive years. The region remains among the top 25 most polluted metropolitan areas in the United States. U.S. Steel's Clairton Coke Works — the largest coke-producing plant in North America — sits 15 miles south of downtown on the Monongahela River, emitting particulate matter, hydrogen sulfide, and sulfur compounds that affect communities throughout the Mon Valley. Research at the University of Pittsburgh found that children living near industrial pollution sources had 58 percent higher odds of developing asthma. Approximately 50,000 children in the metro area have pediatric asthma, and 227,000 adults have asthma. For allergy sufferers, this matters because industrial air pollution compounds the effects of biological allergens. Fine particulate matter (PM2.5) inflames airways independently, reducing the respiratory system's ability to tolerate pollen and mold. Ozone damages airway lining. When a temperature inversion traps both ragweed pollen and industrial emissions in the river valleys simultaneously, the respiratory impact is greater than either would produce alone.
Pittsburgh's industrial history has left dozens of brownfield sites — former steel mills, railroad yards, coke plants, and manufacturing facilities — scattered throughout the river corridors. These sites, often with contaminated or disturbed soils, have become some of the most productive ragweed habitats in the region. Ragweed thrives in disturbed soils and colonizes abandoned industrial land aggressively. The Strip District's edges, the former Hazelwood LTV Steel site (now being redeveloped as Hazelwood Green), abandoned rail corridors in the Mon Valley, and vacant industrial parcels along the Ohio River all support dense ragweed stands. As Pittsburgh's urban redevelopment continues, each construction project temporarily creates new disturbed soil where ragweed and other pioneer weeds establish. The ongoing transformation of former industrial sites into residential and commercial developments alters the local allergen landscape — replacing ragweed habitat with maintained landscaping that produces grass pollen. Neighborhoods near active redevelopment sites may experience temporary spikes in weed pollen during the construction phase before allergen profiles shift to their long-term patterns.
Pittsburgh's dramatic topography creates measurably different allergen experiences across neighborhoods that may be only a mile apart. Low-lying riverfront neighborhoods — the Strip District, Lawrenceville, Millvale, Sharpsburg, and areas along the South Side — experience higher humidity from river evaporation, more frequent morning fog that traps pollen at ground level, greater exposure to temperature inversions that hold industrial emissions, and more mold due to proximity to water. Hilltop neighborhoods — Mount Washington, Squirrel Hill, Shadyside, Highland Park, Observatory Hill — generally have better air circulation, less exposure to temperature inversions, and lower humidity. However, they have greater exposure to tree pollen from surrounding forest canopy and parks. Frick Park (644 acres) and Schenley Park (456 acres) are two of the largest urban parks in the eastern United States, producing substantial tree and grass pollen that affects adjacent neighborhoods. Communities in the Mon Valley corridor — Clairton, McKeesport, Braddock — face the combined burden of industrial emissions and biological allergens in a narrow valley with frequent temperature inversions.
HeyAllergy offers telemedicine appointments with board-certified allergists and immunologists licensed in Pennsylvania. Book a virtual consultation from anywhere in the Pittsburgh metro — Allegheny County, Westmoreland County, Butler County, Washington County, or Beaver County — and connect from home using your phone, tablet, or computer. Have allergy blood tests ordered at a convenient local lab and receive a personalized treatment plan based on your specific triggers. HeyPak sublingual immunotherapy drops ship directly to your door and treat the root cause of allergies by building tolerance to the specific allergens triggering your symptoms — whether oak, birch, Timothy grass, ragweed, dust mites, or mold. In a city where river valley geography and industrial air quality compound the effects of biological allergens, treating the underlying allergic sensitivity reduces the burden your respiratory system carries every day.
April through June is the worst period, when overlapping tree and grass pollen peaks coincide. Oak, birch, and maple tree pollen surge from April through May, followed by Timothy grass and bluegrass peaking in June. August through September brings a second peak from ragweed, compounded by summer ozone and mold. Pittsburgh's river valley geography concentrates these allergens in low-lying neighborhoods.
The most common allergens in Pittsburgh are oak pollen, birch, maple, Timothy grass, bluegrass, ragweed, mold (Alternaria, Cladosporium, Aspergillus), dust mites, and pet dander. Ash, elm, hickory, sycamore, and pigweed also affect residents. A blood allergy test identifies your specific triggers.
Yes. Allegheny County has received failing grades for air quality from the American Lung Association for 20 consecutive years. Fine particulate matter and ozone from industrial sources inflame airways independently, making allergic reactions to pollen and mold measurably more severe. Temperature inversions in the river valleys trap both industrial emissions and biological allergens at ground level, compounding respiratory effects.
Yes. HeyAllergy provides telemedicine appointments with board-certified allergists and immunologists licensed in Pennsylvania. Book a virtual consultation from anywhere in the state, have allergy blood tests ordered at a lab near you, and start a personalized treatment plan without visiting a clinic. No referral needed and no waitlist.
HeyPak sublingual immunotherapy uses customized liquid drops placed under your tongue daily. The drops contain precise doses of the specific allergens triggering your symptoms — whether oak, birch, ragweed, Timothy grass, dust mites, or mold. Over time, your immune system builds tolerance, reducing allergic reactions and medication dependence. Most patients notice improvement within 3 to 6 months.
HeyAllergy accepts Medicare and most major PPO health plans, including United Healthcare, Health Net, Anthem Blue Cross, Anthem Blue Cross Blue Shield, Blue Shield, Cigna, Aetna, Humana, Oscar, and Tricare. Contact your insurance provider with Tax ID: 85-0834175 to confirm your specific telemedicine coverage.
Pittsburgh's three rivers create valley systems that funnel and concentrate airborne pollen. Morning fog traps allergens at ground level. Temperature inversions — where cold air settles beneath warm air — can hold both pollen and industrial emissions in the valleys for days. Neighborhoods at higher elevations generally experience better air circulation and lower allergen concentrations than low-lying riverfront areas.
HeyAllergy offers fast scheduling with no waitlist. Book a telemedicine appointment with a board-certified allergist and connect from home using your phone, tablet, or computer. Pittsburgh and western Pennsylvania residents can access specialist allergy care immediately without waiting weeks for a local opening.
Pittsburgh, Pennsylvania — population approximately 305,000 in the city, 2.3 million in the metro area — presents one of the most complex respiratory environments in the United States. The city sits at the confluence of three rivers (Allegheny, Monongahela, and Ohio) in a valley system flanked by steep hills rising 300 to 400 feet above the water. This geography, combined with a legacy of heavy industry that continues to affect air quality, creates conditions where biological allergens and industrial air pollution compound each other in ways unique among American cities. Allegheny County has received failing grades from the American Lung Association for particulate matter and ozone for 20 consecutive years. The metro area is home to approximately 50,000 children with pediatric asthma and 227,000 adults with asthma. For allergy sufferers, Pittsburgh's challenge is not just pollen — it's pollen trapped in valleys alongside some of the worst industrial air pollution east of California.
Pittsburgh's topography is the foundation of its allergy challenges. The three rivers create valley systems that act as natural channels, funneling and concentrating airborne pollen rather than allowing it to disperse. The confluence at Point State Park creates circular air patterns that keep allergens circulating in the downtown area. Morning fog in the river valleys — a common occurrence in spring and fall — traps pollen at ground level along riverfronts, trails, and low-lying neighborhoods. Temperature inversions, where cold air settles into the valleys beneath warmer air above, create atmospheric lids that prevent both pollution and pollen from dispersing. These inversions can last days during winter months and are responsible for some of the highest particulate matter readings in the eastern United States. The hills surrounding the valleys create what allergists describe as pollen "pockets" — terrain features where allergen concentrations are significantly higher than on ridgetops just a few hundred feet above. A resident living along the Allegheny River in Lawrenceville may experience very different allergen exposure than someone living on Squirrel Hill's ridgetop, despite being only two miles apart. This elevation-dependent variation in allergen exposure is a distinctly Pittsburgh phenomenon, shaped by topography that few other major American cities share.
Pittsburgh's industrial history casts a long shadow over its respiratory health. In the 1940s, smoke and soot from coal and steel plants was so thick that city authorities turned on streetlights at midday. A writer for The Atlantic Monthly in 1868 called Pittsburgh "hell with the lid taken off." The city's transformation to a technology, medical, and education economy is genuine — but the industrial legacy persists in measurable ways. U.S. Steel's Clairton Coke Works, the largest coke-producing plant in North America, sits 15 miles south of downtown on the Monongahela River. In January and February 2026, equipment outages at the facility triggered multiple health warnings from the Allegheny County Health Department for hydrogen sulfide and particulate matter levels that exceeded safe standards. The Mon Valley corridor — Clairton, McKeesport, Braddock, and surrounding communities — has been identified as having the most heavily impacted environmental justice communities in Allegheny County. A 2020 University of Pittsburgh study found children near major industrial pollution sources had 58 percent higher odds of developing asthma. Fine particulate matter inflames airways independently of biological allergens, reducing the respiratory system's tolerance for pollen and mold. When temperature inversions simultaneously trap industrial emissions and spring tree pollen in the river valleys, the combined respiratory burden exceeds what either would produce alone.
Pittsburgh's position on the western edge of the Appalachian Plateau gives it access to one of the most biodiverse temperate deciduous forests on Earth. This botanical richness translates directly into an exceptionally varied tree pollen profile. The forests of western Pennsylvania contain more tree species producing allergenic pollen than virtually any city in the Midwest or Northeast. Oak, maple, birch, ash, elm, hickory, walnut, sycamore, cottonwood, poplar, beech, and pine all grow within the city limits and surrounding hillsides. Each species pollinates at a slightly different time, creating a cascading tree pollen season that can begin with elm and maple in March and continue through hickory and walnut in late May — a nearly three-month procession. Pittsburgh's extensive park system reinforces this diversity. Frick Park's 644 acres and Schenley Park's 456 acres are among the largest urban parks in the eastern United States, containing dense stands of mature deciduous trees. Highland Park, Riverview Park, and dozens of neighborhood parks add thousands more acres of urban forest. The city's commitment to its urban tree canopy is an asset for quality of life but a challenge for allergy sufferers living adjacent to these green spaces.
Pittsburgh's industrial past has left dozens of brownfield sites — former steel mills, railroad yards, coke plants, and manufacturing facilities — scattered along the river corridors. These sites, with their disturbed and often contaminated soils, have become some of the most productive ragweed habitats in western Pennsylvania. Ragweed colonizes disturbed ground aggressively, and the abandoned industrial parcels along the Monongahela, Allegheny, and Ohio rivers support dense stands. As Pittsburgh's urban redevelopment continues — the transformation of the former Hazelwood LTV Steel site into Hazelwood Green, new development in the Strip District, residential construction in Lawrenceville and the South Side — each project temporarily creates new disturbed soil where ragweed establishes. The ongoing construction phase of Pittsburgh's transformation means the city's ragweed allergen load may actually be higher now than it will be when redevelopment stabilizes. For current residents, this means fall ragweed season in neighborhoods near active construction or undeveloped brownfields can be particularly intense, with pollen produced just blocks away concentrating in the river valley terrain traps.
HeyAllergy's telemedicine platform connects Pittsburgh and western Pennsylvania residents to board-certified allergists and immunologists licensed in Pennsylvania. A virtual consultation from home eliminates the need to navigate Pittsburgh's hills and bridges for specialist care — no waiting weeks for an appointment, no sitting in a waiting room. Allergy blood tests are ordered at a convenient local lab in Allegheny County or wherever is most accessible. A personalized treatment plan is developed based on your specific triggers. HeyPak sublingual immunotherapy drops ship directly to your door and treat the root cause of allergies by building your immune system's tolerance to the specific allergens driving your symptoms — from oak and birch pollen to Timothy grass, ragweed, mold, dust mites, and pet dander. In a city where river valley geography and industrial air quality compound the burden of biological allergens, reducing your body's allergic sensitivity provides relief that no air quality improvement alone can deliver.
