AIRE: Atmospheric Information Resource for Educators and students

ICYMI: India’s Air Pollution Crisis, By the Numbers

In this article, published in October 2017 on HuffPost India, Prof. McNeill and Dr. Julia Nunes break down the data for particulate air pollution in cities across India. Air pollution is at an unhealthy level for a large part of the year, in most Indian cities.

The pie charts show the number of days in the past year that the average PM2.5 level fell into the following three categories: Green days (PM2.5 < 35.4 μg m-3) are healthy or moderate, yellow days (35.5 μg m-3 to 55.4 μg m-3) are unhealthy for sensitive groups such as children, the elderly or those with lung disease, and red days (PM2.5 > 55.5 μg m-3) are unhealthy for all. For more information on the data sources:


Live reporting from Beijing: Air Quality in Crisis

V. Faye McNeill, Beijing, China, December 21, 2016

Haze over central Beijing, 12/20/2016. Photo credit: V. F. McNeill

Much of China, including the capital city, Beijing, is experiencing sustained heavy smog this week, with air pollution at hazardous levels for the past three days. Concentrations of fine particulate matter in Beijing’s air today exceeded 400 ug/m3, more than ten times China’s National Ambient Air Quality Standard (35 ug/m3). The episode has caused an increase in hospitalizations and disruptions in air traffic due to poor visibility. The government has declared a “red alert” and taken emergency measures including industrial shutdowns, odd-even traffic restrictions, and school cancellations to protect public health.

“I love Beijing.  I grew up here and spent my whole life here.  If it weren’t for the air pollution, I would love living here.  But now I think about leaving. Many people are leaving.”

Reduced visibility at Beijing’s airport. 12/20/2016 Photo credit: V.F. McNeill

Air quality is an ongoing issue in Beijing, and a major subject of concern for its residents. As one Beijing native told me: “I love Beijing.  I grew up here and spent my whole life here.  If it weren’t for the air pollution, I would love living here.  But now I think about leaving. Many people are leaving.” According to the U.S. Embassy, between 2008-2015, the daily average air quality index in Beijing fell in the “Unhealthy,” “Very Unhealthy,” or “Hazardous” categories 67% of the time. A severe air quality episode in January 2013 was somewhat of a turning point, leading to increased pressure on the government to tighten regulations. One outcome was the amendment of the national ambient air quality standards. Meeting the new standards for PM2.5 would be a major step towards protecting public health. But, as episodes like this one show, improvement is slow to come. Plans for local implementation and enforcement of the new air quality standards are still in the development stages. In some cases major changes in infrastructure are needed in order to reduce emissions, and this can take time. Local efforts alone won’t be enough: The city of Beijing has made bold moves towards eliminating coal burning within the city, but much of Beijing’s pollution comes from upwind sources, outside the city limits.

With the will of government and the people aligned, China is poised to turn around its air pollution problem. Unlike the U.S., which greatly improved its air quality in the last century and now must tackle climate, China is in a position to develop smart new policies and technology to improve air quality and reduce carbon emissions simultaneously.

NYC Air Quality – Improving? AIRE reports!

AII Air Quality NYC - US letter _Page_03ccording to the New York City Department of Health and Mental Hygiene, air quality in NYC is getting better.  Here at AIRE, we hypothesized the opposite last summer.  Based on a very unscientific survey of our own asthma responses and perceptions of visibility in the city, we suspected that summertime air quality had been on the decline in recent years (2014-2015).  To test this hypothesis, summer undergraduate researcher Silvia Vina Lopez gathered Air Quality Index (AQI) data for NYC from 2000-2015, and data on criteria pollutant (SO2, CO, NO2, O3, PM) concentrations from 9 NYSDEC monitoring sites around the five boroughs. Here are some highlights of her findings:

  • Overall, air quality has been improving since 2000.  Importantly, there has clearly been a steady decrease in the number of “bad air days”. Since 2000, the number of days categorized as “Unhealthy for sensitive groups,” “Unhealthy,” or “Very unhealthy” has been on the decline.
  • Since 2008, the number of “Good” air quality days has had an overall upward trend, but there indeed has been a sharp decrease in “Good” days since 2013.  Since “Moderate” air quality is also pretty good in the big scheme of things, this trend may be subtle to perceive as you’re walking the streets of NYC unless you have asthma (like us) or think about PM 2.5 a lot (also like us).

II Air Quality NYC - US letter _Page_04To dig deeper into these trends, Silvia investigated the frequency with which each criteria pollutant exceeded the 24 h NAAQS standards. She found that SO2 violations decreased between 2004-2009 and have stayed low. The City attributes this trend to changes in heating oil regulations. On the other hand, the frequency of PM2.5 violations increased over the same time period and has remained elevated since 2009. This value decreased somewhat between 2007-2015, consistent with the data presented in the City’s survey, which covered 2008-2014. However, the average number of PM2.5 violations 2009-2015 was still significantly higher than 2000-2005.

The verdict: air quality in NYC is not bad and getting better in general.  However, work needs to be done to reduce PM2.5 violations, and hold on to the gains made between 2008-2014.  One possible source of elevated PM2.5 not mentioned in the City’s report is secondary organic aerosol formation: the formation of PM2.5 in situ, due to gas-phase reactions of oxidants and volatile organic compounds (which can be natural or man-made).

Recommended Resource: “What’s Up in the Atmosphere? Exploring Colors in the Sky,” an aerosols storybook from The GLOBE Program

Scientists and educators from NASA and UCAR have written a storybook entitled “What’s Up in the Atmosphere? Exploring Colors in the Sky” aimed at elementary school-aged (K-4) children, in which atmospheric aerosols play a starring role.  The story follows a group of curious students who, under the guidance of their teacher, investigate the connection between the appearance of the sky and asthma symptoms in their fellow students on a given day.  The students in the story (and the readers) learn about atmospheric aerosols in the process.  The storybook includes a teachers’ guide with glossary.

Air Quality in Manila, Philippines

The AIRE team spends a few weeks every year visiting family in Manila, Philippines.  Like many vibrant megacities, Manila suffers from heavy traffic and poor air quality.  Starting in Summer 2015, the Philippine government has made real-time air quality monitoring data available from stations around Metro Manila.  Interested citizens can look up current PM2.5 levels and compare them to the 24 hour guideline value.  We note that the EMB 24 hr guideline value is 75 micrograms/m3, whereas the United States EPA 24-hour average PM2.5 standard is 35 micrograms/m3 (the yearly average standard is 15 micrograms/m3).

Quick Facts About Indoor Air

This long winter has had the AIRE team thinking about the amount of time we spend indoors, and the air quality there.

– These days, most people spend the vast majority of their time indoors (especially in the winter!). There is therefore high potential for exposure to pollutants indoors, i.e., at home or in the workplace.

– While what we think of as commonplace outdoor pollutants (e.g. car exhaust) may be less prevalent indoors than outdoors, other chemicals such as volatile organic compounds (VOCs) can be present at much higher concentrations indoors. Indoor VOCs may come from many sources including cleaning products, air fresheners, and new furniture. They can harmful to health on their own, or serve as precursors for the formation of aerosol particles.

– You have probably heard about secondhand smoke, which is the exposure of non-smokers by being around smokers. Thirdhand smoke can also be a problem. This occurs when nicotine, tar, and other harmful chemicals in tobacco smoke deposit on indoor surfaces like walls and carpets. People can be directly exposed to these chemicals through contact the surface, or reactions with gases like ozone may cause them to re-enter the gas phase.

We are looking forward to the warmer weather and more time in the fresh air outdoors!

Recommended Resource: Aerosol Science & Engineering

In honor of the 2014 Annual meeting of the American Association for Aerosol Research, happening this week in Orlando, FL,  we are very excited to share with you this series of educational modules on the science and engineering of aerosols (airborne particles).

These materials were developed by Profs. Pratim Biswas, of Washington University St. Louis, and C. Y. Wu, of University of Florida, through a collaborative grant from the National Science Foundation. The modules are aimed at an introductory college level, and are excellent for supplementing course materials or learning on your own.

The modules:

The complete lecture series for an introductory course on Aerosol Science and Technology from WUStL is available FREE through ITunesU!:

Additional information on this effort, and more resources:


De la saca de correos: “Mi hija tiene asma. ¿De qué manera la contaminación del aire afecta a su salud?”

Pregunta: Mi hija tiene asma. ¿De qué manera la contaminación del aire afecta a su salud? – M.N., New York, NY

Respuesta: Las personas asmáticas son muy sensibles a los efectos de la contaminación del aire. Al respirar el aire contaminado, esto puede desencadenar o empeorar los síntomas del asma.  El ĺndice de Calidad del Aire (AQI) es una medida que nos dice que tan ‘saludable’ es el estado actual del aire que respiramos. El AQI se calcula por los niveles de unas sustancias presentes en el aire, las cuales pueden afectar la salud humana, por ejemplo el ozono y la materia particulada. Un nivel AQI sobre 101 no es saludable para la gente asmática, mientras que para los adultos con un buen estado de salud y sin asma, un nivel de AQI sobre 151 no es saludable.

La Prof. McNeill también tiene asma y en los días con alto AQI, ella no se siente bien y usa más el inhalador. Cuando ella estudiaba en la universidad Caltech, cerca de Los Angeles, la calidad del aire fue muy mala, peor que hoy, y esto la motivó a estudiar la química atmosférica.



From the mailbag: “What does the air quality index measure, and what values correspond to ‘good’ air quality?”

Question: What does the air quality index measure, and what values correspond to ‘good’ air quality? – T.L., Manila, Philippines

Answer: Good question! The Air Quality Index (AQI) is calculated based on the concentrations of different pollutants in the air, including atmospheric particulate matter, ozone, carbon monoxide, sulfur dioxide, and nitrogen dioxide.  According to the U.S. EPA, an AQI of 0-50 corresponds to “good” air quality. AQI of 51-100 is “moderate.” When AQI is 101-150, the conditions are “unhealthy for sensitive groups” such as asthmatics, children, and the elderly. AQI of above 151 is considered unhealthy for everyone.

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