Air Pollution: Monitoring Methods And Techniques

Air pollution is a serious issue that affects people's health and the environment. While it is largely beyond an individual's control, there are ways to check the air quality in your area and take action to reduce exposure to harmful pollutants. Air quality can be assessed through various means, including national surveys, real-time air pollution maps, and at-home or professional testing kits. These tools help identify the presence of pollutants such as carbon monoxide, nitrogen dioxide, and particulate matter, enabling individuals and communities to make informed decisions about their health and well-being.

Air Quality Index (AQI)

The Air Quality Index (AQI) is a tool used to communicate information about outdoor air quality and health. It is a scale that runs from 0 to 500, similar to a thermometer, and indicates the amount of pollution in the air. The higher the AQI value, the greater the level of air pollution and the more significant the health concern. For instance, an AQI value of 50 or below signifies good air quality, whereas a value over 300 represents hazardous air quality. When AQI values are above 100, the air quality is considered unhealthy, initially for certain sensitive groups, and then for everyone as values increase.

The AQI is based on the measurement of six key pollutants: particulate matter (PM2.5 and PM10), ground-level ozone (O3), nitrogen dioxide (NO2), sulfur dioxide (SO2), and carbon monoxide (CO). These pollutants are monitored by instruments on the ground and satellites orbiting the Earth, such as NOAA's GOES-R and JPSS series of satellites. The data collected by these instruments and satellites is used to create real-time air pollution maps, providing information on air quality for over 80 to 100 countries.

The AQI is an essential tool for raising awareness about air quality and its potential health impacts. By understanding the AQI, individuals can take necessary precautions to protect their health and well-being, especially in areas with high levels of air pollution. Additionally, the AQI helps in identifying sources of pollution and implementing measures to improve air quality, thereby benefiting the environment and public health.

It is worth noting that the AQI values are subject to change and may be amended without notice due to quality assurance. This flexibility ensures that the data remains accurate and up-to-date, reflecting the dynamic nature of air quality, which can fluctuate daily.

Air Quality Monitors

There are various types of air quality monitors available. Some are designed to be carried on a keychain or necklace to measure the air quality wherever you go. There are also apps that can be downloaded on your phone to check the air quality. These include the AirNow app, which provides air quality information at the local, state, national, and world levels. The AirNow app is free to download and is ad-free. Other apps like AirCare and Airly serve ads in their free versions.

There are also indoor air quality monitors available that can be placed in your home. These monitors can measure various air-quality factors, including CO2, PM2.5, VOCs, and radon. Some examples of indoor air quality monitors are the AirVisual, the Zen Air by PurpleAir, and the Qingping Air Monitor. The AirVisual monitor measures PM 2.5 and CO2, and displays the temperature and humidity. It also has an easy-to-read dashboard on the app and keeps data for a year. The Zen Air monitor uses the EPA AQI color scale to indicate the air quality: green for good air, yellow for moderate, orange for unhealthy for sensitive groups, red for unhealthy, purple for very unhealthy, and deep violet/maroon for hazardous. The Qingping Air Monitor is intuitive to use and acts as a great standalone device without the app. It also has a responsive and helpful support team.

It is important to note that not all air quality monitors are accurate. Some monitors may show incorrect readings, especially for volatile organic compounds (VOCs). Therefore, it is recommended to check reviews and accuracy tests before purchasing a monitor. Some organizations, such as South Coast AQMD, conduct accuracy tests on air quality monitors, and their database can be a good source of information.

Online, Phone and Teletext Services

There are many ways to check air pollution data online. The World Air Quality Index provides a real-time air pollution map for more than 80 countries. The Air Quality Index is based on the measurement of particulate matter (PM2.5 and PM10), Ozone (O3), Nitrogen Dioxide (NO2), Sulphur Dioxide (SO2) and Carbon Monoxide (CO) emissions. The GAIA air quality monitor uses laser particle sensors to measure these pollutants and provides historical data for specific cities. IQAir also provides a similar interactive world map with real-time air quality data.

AirNow is a coalition of US governmental and tribal agencies that monitor air quality in the US, Canada, and Mexico. The website provides a colour-coded AQI, displays primary pollutants and their concentrations, and shows a map of current air quality. AirNow is available on the web and via iOS and Android apps. The Weather Channel, Apple Weather, and AccuWeather apps also provide AQI data. Apple Maps and Google Maps also feature built-in air quality data.

There are also many apps that provide AQI data. 'My AQI Air' is a simple app that provides an overall AQI rating and a breakdown of individual pollutants, as well as environmental factors such as temperature, wind speed, humidity, and air pressure. 'Check Air Quality' is another free app that provides an overall AQI and a detailed breakdown of individual pollutants, as well as a map feature. This app contains advertisements, which can be removed for a one-time fee of $9.99. AirVisual is another app that provides AQI data and has Apple Watch support.

In addition to online services, many countries have phone services that provide air quality data. For example, in the US, the National Air Quality and Weather Hotline provides air quality information for over 400 US cities.

Professional Testing Services

Air quality testing is an important service that can help identify harmful pollutants in the air that may be detrimental to human health. Professional air quality testing services are offered by companies with extensive experience in pollution control, regulatory compliance, and monitoring services.

These companies employ environmental professionals who conduct indoor, ambient, and stack testing to meet CPCB norms and protect health. The process typically begins with a site inspection and sampler placement. Air samples are then collected using specialised equipment, such as High Volume Samplers, and sent to certified laboratories for analysis. The laboratories generate detailed reports that outline pollutant levels, compliance status, and recommendations for improving air quality.

The cost of professional air quality testing can vary depending on several factors, including the size of the area being tested, the number of toxins being tested for, and the sensitivity of the test. For example, a professional radon inspection can cost up to $800, while asbestos air quality testing can range from $287 to $585.

It is recommended that homeowners test their air quality every 3 to 5 years, especially if they are experiencing respiratory health issues or allergies. By identifying elevated levels of allergens, mold, radon, and other harmful compounds, professional testing services can help homeowners ensure the safety and well-being of their families.

Lichen as a Natural Indicator

There are several ways to check air pollution, including at-home tests, professional tests, and the use of air quality monitors. Air quality monitors can check for particulate matter like dust and allergens, as well as chemical pollutants like volatile organic compounds, humidity, and temperature levels. Carbon monoxide detectors are also essential for alerting you to any leaks.

Lichens are a natural indicator species that can be used to determine the air quality in a given area. They are sensitive to a number of air pollutants, including sulphur dioxide, nitrogen dioxide, and other acidic pollutant gases, heavy metals, and photo-oxidants. The presence or absence of lichens, as well as the variety of lichen species in an area, can indicate the level of pollution. Lichens are miniature ecosystems made of a symbiotic relationship between a fungus and an algae and/or cyanobacteria. Their unique biology and ability to absorb more SO2 for a given concentration than typical vascular plants make them excellent indicators of sulphur dioxide pollution.

While lichens are useful indicators, they are limited in that they can only monitor nitrogen and sulphur dioxide levels, and they cannot provide immediate feedback on exact pollution levels, only averages over a longer period. Different lichen species also have varying sensitivities to air pollutants, with crustier lichens generally being more hardy than hairy lichens. For example, the golden shield lichen can live in areas with high levels of nitrogen, especially ammonia, and is commonly found near farmland and on sea cliffs.

In Germany, two methods have been used to employ lichens as indicators: exposing lichens to controlled amounts of nitrogen and recording their growth, and studying the growth of lichens on trees under natural conditions. The Dutch have also developed a method of classifying lichens into "nitrophyte" species, which thrive in high-nitrogen environments, and "acidophyte" species, which prefer low-nitrogen environments.

Frequently asked questions