Are you wondering what the different colors and numbers below mean?
The numbers are the Air Quality Indexes, which is based on a scale from 0 (good) to 500 (bad).The colors correspond to the different health impact categories (good, moderate, unhealthy... hazardous)
Back in 2008, when the World Air Quality project started, all of the existing air quality monitoring stations where based on highly professional and expensive BAM and TOEM technology. This kind of stations are always maintained by professional and highly qualified operators - and this ensures that the output of this station can be trusted.
12 years later, the BAM and TOEM stations still do exist. But with the development of laser scattering technology and low-cost dust sensor, the BAM and TOEM stations are now outnumbered by immense and dense low-cost sensor networks. Nowdays, there are just so many of those networks - to name a few: urad, luft-daten, airqo, airbg, opensense, yakkaw, econet, airkaz, ccdc, ambente, green air, etc..
A common question asked is why are nitrogen dioxide (NO2), sulphur dioxide (SO2) and carbon monoxide (CO) concentrations always so low and is measuring them useful?
To highlight the importance of monitoring these substances this article is going to explain where these pollutants come from and how to they affect our health and the environment.
To keep things short this article will just focus on NO2.
It is already several months since the US EPA updated its AQI standard for Ozone 8 hours breakpoints. This is definitely a positive step towards strengthening Air Quality in the USA, since the US EPA Standard was actually among of the least conservative standard for Ozone, compared, for instance, to similar standards in India, China or Europe!
But more interestingly, AirNow recently took a step further by introducing the Ozone NowCast formula, which allows to use the weighted 8 hours breakpoint standard in place of the 1 hour breakpoint. This change, which the AirNow team did not widely communicate to the public, makes quite a change to the way Ozone AQI is reported, and this is what we will be looking at in this article.
During the past months, the World Air Quality team has been working on analyzing several new Air Quality forecast models, as well as improving the Air Quality forecast model demonstrator.
This article will present the latest forecast model demonstrator, which is based on the Gridded Population of the World (GPW), and which will be applied to analyze the Air Quality forecast for the Northern India region (including Bangladesh, Pakistan and Nepal).
A perfect dust storm (attribution)
We have been writing quite a few times about the influence of wind on air pollution, and how strong winds (or, to be more precise, strong ventilation) can help to clean the air in a very short time. But we never had the opportunity to create on a dynamic visualization of this phenomenon, so this is what this article will be writing about.
It is almost two months since our colleagues from the UNEP have been making an interesting move towards promoting the idea that Air Quality is as important as any other business within the United Nations. They started to invest in this domain, and came up with the excellent initiative to create an open footprint for affordable Air Quality Monitoring Stations.
Map Overlay Process
(Attribution: Essentials of
Geographic Information Systems )
We have been recently cooperating with quite a few more EPAs (environmental protection agencies) world-wide. Among all the requests which we have had, it is actually to provide a Web Map Service so that the EPA themselves can include the real-time Air Quality data onto the map from their website.
One of the obvious advantages of using such a map web service from us is to benefit from the trans-boundary data which we are curating, i.e. a world-wide Air Quality information is provided without country boundary limits.
The second advantage is not only that this is a free service, but it is also completely compatible with standard map technologies from google, bing or leaflet, which allows a quick and easy integration with any existing website.
(Attribution: WMO GAW research on reactive gases )
Unlike particulate matter (PM2.5), the ground-level Ozone is not emitted directly. It is instead produced through a series of chemical reactions that occur in presence of nitrogen oxides, volatile organic compounds, sunlight and high temperatures, as shown on the following visual:
Quantifying the impact of this ground level Ozone on Health is done via the Air Quality Index standard which each country defines. What is interesting is that half of the world is using a standard based on milligrams measurement, while the rest is using ppb based measurement. But is this really a problem? This is what we will be looking at in this article.
Inspekcja Ochrony Środowiska.
(Inspection of Environmental Protection)
The Air Quality data for Poland has been available for a while, but we recently got few questions about the AQI scale used by the Inspekcja Ochrony Środowiska, i.e. the regional inspections of Environmental Protection, and how it differs with the scale used on the World Air Quality Index project. One of them is from Sylwia, who asked:
I am confused with all those numbers, and why there is a difference with the numbers shown on the Warsaw EPA website.
Could you please kindly inform me about the source of the data in Warsaw and the reliability of the data you provide with?
This is actually a very good question, since, when it comes to data, no one should take data as "granted" (refering to the excellent TED talk from Talithia Williams on 'Own your body's data'). This is also the reason why the World Air Quality Index project exists, i.e. to explain every one how to understand the number behind air pollution.
In order to improve the integration of our AQI widgets within external websites, we have developped a new widget API feed. Compared to the existing widget feed, this new API feed provides much more flexibility for the integration, but also many more options for customzing the widget appearance.