In the spring, ammonia (NH 3) concentrations increase drastically due to agricultural activities. Does the air quality differ with the changing seasons? In 1980, 156 days were classified in the US AQI “unhealthy” category, dropping to 90 unhealthy days in 1990, 29 unhealthy days in 2000, and 10 unhealthy days in 2018. A snapshot of these improvements is clearly represented by looking at data on the year of each new decade. Philadelphia annual air quality index (AQI) levels have gradually improved since 1980. In this same report, the Philadelphia-Reading-Camden area was found to rank 23 rd for worst ozone pollution nationally out of 229 included metropolitan areas. 2 Federal regulations mandate that the number of unhealthy ozone days should not exceed an average of 3.2 across two years.įrom 2016 to 2018, Philadelphia experienced an average of 10.8 weighted days of unhealthy ozone, far above the legal limit. In 2019, the American Lung Association rated Philadelphia an “F” for ozone pollution for the city’s failure to meet federal attainment levels. 1 In the summer months, high ozone levels are frequently spread across several states. Since a variety of volatile precursor pollutants can create ozone, it can be more challenging to manage.Īttributing heightened ozone levels to specific emission sources is a near-impossible endeavour.įurther complicating this matter, gas pollutants such as ozone and ozone precursor pollutants do not easily settle and have the ability to travel great distances. This property of atmospheric formation differs from other frequently monitored pollutants which tend to be emitted directly from ground sources. Ozone is a gas pollutant formed from precursor pollutants suspended in the atmosphere and reacting in sunlight. Philadelphia’s air quality is primarily afflicted by ozone. It was noticed that the previous three years have been the hottest for quite some time which adds to the ease of ozone production. ![]() This level worsened for the second year in a row. However, Philly was not so lucky when the levels of ozone were measured. The concentration level of Particulate Matter of PM2.5 fell for the seventh consecutive year. There were mixed reactions to the figures. In 2019, the American Lung Association’s 2019 “State of the Air” report was made available to the public, as they do every year. Why is the air quality bad in Philadelphia? 2019 saw a slightly worse figure of 10.5 µg/m³ before it improved again in 2020 with a 9.5 µg/m³ reading. Looking back at the annual figures on the IQAir website, it can be seen that Philadelphia’s air quality remains fairly stable. Only for the month of November did Philly see “Moderate” air quality with readings between 12.1 and 35.4 µg/m³. During the months of February, July, August and December, the air quality was in the “Good” category with figures between 10 and 12 µg/m³. 3įor 7 months out of the year in 2020, Philadelphia achieved the WHO target figure of 10 µg/m³ or less. Importantly, health experts stress that no level of PM2.5 exposure has been shown to be free of health impacts. In 2019, Philadelphia’s average annual PM2.5 level of 10.3 μg/m3 fell between these two standards, meeting the EPA target but exceeding the WHO standard. ![]() While the US Environmental Protection Agency (EPA) requires PM2.5 levels not to exceed 12 μg/m3, the World Health Organisation (WHO) targets a more stringent standard of 10 μg/m3. These annual pollution averages, however, obscure Philadelphia’s pollution events which give way to unhealthy pollution days (referred to as “action days”). The Delaware Valley's population of 7.2 million makes it the eighth-largest combined statistical area in the US.ĭespite seasonal and daily fluctuations into “moderate” and “unhealthy” AQI ratings, Philadelphia has, in recent years, consistently averaged an annual AQI level in the “good” category. ![]() Philadelphia is acknowledged as being the economic and cultural centre of the greater Delaware Valley along the lower Delaware and Schuylkill rivers. Philadelphia, affectionately known as Philly, is the largest city in the US state of Pennsylvania and the sixth-most populous city in the States, with a 2019 estimated population of just over 1.5 million people. What is the state of air pollution in Philadelphia, now?
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