Measuring Air And Water Pollution: Effective Strategies And Techniques

Air and water pollution are two of the most pressing environmental issues facing the world today. With air pollution causing approximately 7 million premature deaths per year, and water pollution threatening the health of aquatic ecosystems, it is crucial to be able to measure the quality of these essential substances. This allows for the identification of hotspots and the implementation of targeted actions to improve and protect the health and well-being of both humans and the environment.

There are several methods and tools available to measure air and water pollution.

Air pollution measurement methods

Air pollution can be measured in several ways, and these methods help public health officials assess current air quality, predict future trends, and develop strategies to improve health conditions. Here are some of the most common air pollution measurement methods:

Air Quality Index (AQI)

The Air Quality Index is a widely used tool for communicating outdoor air quality and its potential health risks. The AQI is a numerical system, with higher values indicating worse air quality. In the US, the Environmental Protection Agency (EPA) has established an AQI with six colour-coded categories, each representing a different level of health concern. For instance, a value of 50 or below signifies good air quality, while a value over 300 indicates hazardous air quality. The AQI is a useful metric for the public to quickly assess the air quality in their communities.

Satellite Imaging

Satellites orbiting the Earth are equipped with instruments that can monitor and collect data on various particles in the air, such as smoke from wildfires, dust from storms, industrial pollution, and volcanic ash. Satellites like the GOES-R Series and the Joint Polar Satellite System (JPSS) provide frequent and high-resolution measurements of particle pollution and aerosols. Additionally, satellites can track the movement of these particles across the planet, aiding in the identification of air pollution hotspots.

Ground-Based Monitoring

In addition to satellite technology, ground-based instruments play a crucial role in air pollution measurement. These instruments are often outfitted with sensors designed to detect specific pollutants, such as particulate matter (PM2.5 and PM10), ground-level ozone, nitrogen dioxide, and sulfur dioxide. Some of these sensors utilise lasers to scan and determine the density of particulate matter in a given volume of air. This data is essential for governments and organisations to address air pollution and protect human and environmental health.

Air Pollution Calculators

Public health officials can use air pollution calculators to focus on specific pollutants, such as carbon monoxide. By inputting a pollutant and its AQI level, the calculator provides the concentration level and corresponding health impact statements. This tool assists in quantifying the potential risks associated with different pollutants and helps officials make informed decisions to protect public health.

Ambient Air Quality Monitoring

This monitoring method involves measuring ambient air pollutant samples to compare current atmospheric conditions with historical data and clean air standards. By analysing the levels of various pollutants in the air, this approach helps identify areas of concern and track progress towards improving air quality.

These methods of air pollution measurement provide valuable insights for governments, organisations, and health officials to address the pressing issue of air quality deterioration and its impact on human health and the environment.

Passive and active air pollution measurement devices

Air pollution is broadly measured in two ways: passively or actively. Passive devices are relatively simple and inexpensive. They collect ambient air samples, which are then analysed in a laboratory. Diffusion tubes, fastened to objects like lamp posts, are among the most common forms of passive measurement. They absorb specific pollutant gases, which are then analysed in a laboratory. Deposit gauges, large funnels that collect soot and other particulates, are another type of passive device and are one of the oldest forms of pollution measurement.

Active measurement devices are automated or semi-automated and tend to be more complex and sophisticated than passive devices. They use fans to suck in the air, filter it, and either analyse it automatically or store it for later laboratory analysis. Active sensors use physical or chemical methods. Physical methods measure an air sample without changing it, for example, by seeing how much of a certain wavelength of light it absorbs. Chemical methods change the sample through a chemical reaction and then measure it. Most automated air-quality sensors are examples of active measurement. They range from small handheld devices to large-scale static monitoring stations in urban areas.

Direct-reading air quality monitors provide information at the time of sampling, enabling rapid decision-making. They are particularly useful for identifying point source contamination or emissions, such as gas leaks, and for screening surveys to determine areas requiring further evaluation. Active sensors can also be used to monitor the effectiveness of ventilation systems and local exhaust systems.

Personal sensors empower individuals and communities to better understand their exposure to air pollution. For example, a research group led by William Griswold at UCSD distributed portable air pollution sensors to commuters and found that passengers in buses were exposed to higher levels of pollution than those in cars. Portable sensors can also be used to monitor air quality across wide areas. Their data can be used in a crowdsourced way, either alone or with other pollution data, to create maps of pollution.

Health impacts of air pollution

Air pollution is a mix of hazardous substances from both human-made and natural sources. It is a major threat to global health and prosperity, causing more than 6.5 million deaths each year worldwide. This number has increased over the past two decades. The main pathway of exposure to air pollution is through the respiratory tract, which can lead to inflammation, oxidative stress, immunosuppression, and mutagenicity in cells throughout the body, impacting the lungs, heart, and brain, among other organs.

Particulate matter (PM), carbon monoxide (CO), ozone (O3), nitrogen dioxide (NO2), and sulphur dioxide (SO2) are among the pollutants with the strongest evidence for public health concern. Fine particulate matter, such as PM2.5, is of particular concern as it can be inhaled deeply into the lungs, enter the bloodstream, and travel to organs, causing systemic damage to tissues and cells. This can lead to reduced lung function, respiratory infections, and aggravated asthma from short-term exposure. Long-term or chronic exposure to fine particulate matter increases the risk of non-communicable diseases such as stroke, heart disease, chronic obstructive pulmonary disease, and cancer.

Children, the elderly, and pregnant women are more susceptible to air pollution-related diseases. Maternal exposure to air pollution is associated with adverse birth outcomes, such as low birth weight, pre-term birth, and small gestational age births. Additionally, air pollution may affect neurological development in children, with a growing body of evidence suggesting a link to diabetes.

Occupational exposure to certain industrial chemicals, such as benzene, has been linked to specific health risks. A study found that living near major roadways may increase a woman's risk of developing breast cancer. Furthermore, psychosocial stress, such as poverty and racial/ethnic discrimination, can amplify the harmful effects of air pollution.

Water pollution: chemical pollution of surface water

Water quality monitoring is essential to understand the health of an ecosystem and determine if the water is usable, consumable, and safe to swim in. Water pollution from chemical contaminants poses a significant risk to human and ecological health, and developing methods to measure and manage these contaminants is crucial.

Chemical pollution of surface water, including oceans, lakes, rivers, and groundwater, can be assessed through various physical and chemical measurements. These measurements provide data on several parameters that indicate the health of the water body.

One critical parameter is pH, which measures the acidity of the water. Accurate pH testing is essential for ensuring water safety and preventing disease risk. Another important measurement is water temperature, which indicates the metabolic rate of aquatic life and their sensitivity to pollution and diseases. Conductivity, or the water's ability to conduct electricity, provides information about the substances dissolved in the water.

Other key chemical characteristics include dissolved oxygen levels and nutrient concentrations. Dissolved oxygen levels can indicate the presence of pollutants and their impact on aquatic life, while nutrient concentrations can reveal the presence of excess fertilizers or other contaminants.

To detect and quantify chemical pollutants, advanced monitoring equipment and analytical techniques are employed. For example, the US Environmental Protection Agency (EPA) has conducted studies on the Colorado River, utilizing bioeffects-based monitoring and analytical chemical measurements to assess the impact of a wastewater treatment plant. Additionally, the EPA has developed methods to detect waterborne contaminants, including per- and polyfluoroalkyl substances (PFAS) and algal toxins, which are of emerging concern.

By employing these measurement techniques and conducting research, we can better understand and manage chemical pollution in surface water, ensuring the protection of our water resources and the health of both people and the environment.

Air pollution sensors

There are a variety of air quality monitors available on the market, with varying features and price ranges. Some monitors measure only PM 2.5, while others can measure a range of pollutants, including PM 10, CO2, VOCs, temperature, and humidity. It is important to note that VOC sensors are particularly useful for indoor air quality monitoring, as VOCs tend to pose a greater threat indoors. Some advanced monitors also feature additional sensors for radon and carbon monoxide, which are more dangerous for both short-term and long-term exposure.

The Govee Smart Air Quality Monitor, for example, is one of the most affordable options, offering a user-friendly app and an easy-to-read screen that displays PM 2.5, temperature, and humidity. On the other hand, the QP Pro Air Quality Monitor is a more comprehensive monitor, measuring PM 2.5, VOCs, CO2, temperature, and humidity, but it may be less user-friendly due to its small touchscreen display.

Another popular option is the PurpleAir monitor, which offers real-time air quality data for over 80 countries. PurpleAir provides two types of outdoor air monitors: the PurpleAir Classic Air Quality Monitor and the PurpleAir Classic SD Edition, which can store data without Wi-Fi. They also offer an indoor air quality monitor, the PurpleAir Touch, which measures PM 2.5 and indicates air quality using a colour-coded LED ring.

When choosing an air pollution sensor, it is important to consider the specific pollutants you want to measure and select a monitor with the appropriate sensors. Additionally, features such as connectivity, customisation options, and notifications for harmful pollutant concentrations should be taken into account to ensure the monitor suits your needs.

Frequently asked questions