How does air pollution affect human health?
High air pollution episodes resulting from forest fires, regional haze, and crop residue burning elevate concentrations of gaseous pollutants and fine particulate matter (PM2.5). The tiny particles present in the ambient air can penetrate deep into the lungs and even enter the bloodstream, causing various health effects such as respiratory infections, asthma, chronic obstructive pulmonary disease (COPD), cardiovascular diseases, stroke, diabetes, and premature mortality. Epidemiological studies (research on how and why diseases occur in different groups of people) so far have revealed that even a short-term exposure for few hours or a few days to elevated PM2.5 levels can increase the risk for hospital admissions for respiratory and cardiac conditions, especially among vulnerable groups like children, older people, and people with pre-existing health conditions such as asthma, heart diseases or diabetes, or even outdoor workers.
Across South Asia, the proportion of outdoor workers is proportionately higher, and they are particularly susceptible to the harmful effects of severe pollution events. These vulnerable groups include street vendors, rickshaw (three-wheeled passenger cart) drivers, and construction labourers.
Beyond physical health, high-pollution events can also exacerbate mental health conditions such as anxiety and depression, as people are often forced to limit outdoor activities. High episode events significantly affect visibility, disrupting transportation, increasing accidents and delays. Together, these can have an impact on local businesses and tourism, ultimately reducing both local and national income. This was the case in Kathmandu Valley in March 2025, when smoke from widespread forest fires in the plains travelled long distances and significantly deteriorated the valley’s air quality. This spike in pollution showed how a single pollution event can affect areas far from its source. This underscores that air pollution from such episodic events is not just a local issue, but a broader public health and environmental concern. To stay safe during such episodes, it is important that individuals and families minimise exposure and stay safe during high pollution episodes. Below are some of the tested measures to follow:
Protecting yourself from pollution
Avoiding exposure during high pollution events is the most effective strategy for protecting individuals across all age groups. However, not everyone can afford to stay indoors, as daily responsibilities for work, commuting, and other essential activities often require outdoor exposure. While vulnerable groups such as children, older people, and individuals with pre-existing health conditions may be able to stay indoors during such periods, attention must also be given to indoor air quality, which can still pose significant health risks if not properly managed.
For those who need to commute, it is recommended to wear a well-fitted proper mask, avoid highly polluted areas like heavy traffic areas, smoky burning areas, if possible, etc. Along with these, other protective measures are explored further throughout this article.
Use of air purifiers in indoor environments
Air purifiers are now available widely. This is increasingly becoming one of the most sought-after solutions to reduce exposure in indoor environments during high air pollution episodes. Earlier, these devices were mostly confined to hospitals or homes with elderly or critically ill individuals. In the last few years, their use has expanded, particularly in severely polluted urban centres like Delhi and Kathmandu, which experience frequent and longer duration of pollution peaks.
High-efficiency particulate air (HEPA) filters used in air purifiers are known to significantly reduce indoor PM2.5 concentrations, offering measurable respiratory benefits, especially for vulnerable groups. However, while effective, the economic burden of purchasing and maintaining purifiers can limit access for low-income households, raising questions of equity and sustainability. In such cases, there are low-cost do-it-yourself (DIY) air cleaners made using simple materials like a box fan and a furnace filter. This method, developed by the United States Environmental Protection Agency (EPA), provides an affordable and accessible option for improving indoor air quality. Experts recommend properly sealing windows and avoiding indoor pollution sources to improve the effectiveness of air purifiers.
Choosing the right mask
Wearing face masks can provide a useful layer of personal protection. It is important to note that mask fit, and sealing play a crucial role in overall effectiveness. One simple yet effective way for people to protect themselves from harmful pollutants such as PM2.5 is by wearing the right type of mask. However, not all masks offer the same level of protection. If wearing a mask feels suffocating, causes discomfort, or leads to dizziness, especially during intense physical activity, it is advisable to remove it.
N95 masks typically offer the highest protection, effectively filtering out at an efficiency ranging from 64% to over 97% for airborne particles, including PM2.5. Surgical masks also provide moderate protection (efficiency between 56.3% and 83.2%), mainly against larger respiratory droplets but less against fine particulates; these are more effective than standard cloth masks, which showed significantly lower filtration performance. Alternatives such as muslin and sponge masks, face wash tissues, and cotton or other fabric masks are known to provide limited or no protection.
Right fit and comfort of mask is also equally important, as Dr. Meghnath Dhimal, Chief Research Officer, at Nepal Health Research Council explains, “Using the right kind of respirator mask, particularly during high air pollution events, is one of the simplest and most effective ways to reduce personal exposure to fine particles. But it is equally important to ensure the mask fits properly”.
Staying informed
Stay updated on air pollution levels in your locality through various online platforms such as https://www.iqair.com [1], https://www.airnow.gov [2], smog.icimod.org [3], pollution.gov.np, [4] and airquality.cpcb.gov.in [5], airquality.cpcb.gov.in [5] provide real-time air quality information, helping individuals prepare and take necessary precautions to reduce exposure.
- Avoid exercising or jogging outdoors on days with high Air Quality Index (AQI, air pollution level).
- It is a good practice to avoid walking, jogging, or running close to busy roads.
- Keep children, older people, and individuals with medical conditions such as asthma or heart issues indoors when AQI is high.
Diet
Diet and nutrition also play a supportive role in reducing the impact of air pollution. Health professionals often recommend eating antioxidant-rich foods, such as fruits, vegetables, and nuts, that help combat inflammation. Additionally, consuming antioxidant-rich foods is known to reduce inflammation triggered by air pollution and other and other environmental stressors, thereby supporting overall respiratory and cardiovascular health. In addition, staying well hydrated during high pollution events is beneficial, especially when exposure is unavoidable. Proper hydration supports the body’s natural detoxification processes and can help cope with pollutants more effectively. Dr. Ram Krishna Chandyo, Associate Professor at the Department of Community Medicine, Nepal Medical College, suggests that “Hydration and nutrition are often overlooked in discussions on combating the impact of air pollution. But staying well-hydrated and eating a diet rich in antioxidants can help strengthen the body’s resilience to pollution-induced stress.”
Positive mindset
Air pollution can affect not just our physical health but also our mental well-being. It is important to maintain a positive mindset, especially if there is a limited opportunity to be outdoors. Encouraging practices in relaxation techniques can help mitigate stress and anxiety, which are often exacerbated by poor air quality.
Staying safe during high pollution episodes needs both awareness and action. While systematic solutions must come from governments’ regulations and policies, each of us also needs to do a lot through behavioural change. By staying updated, making small daily changes, and using tools like masks and purifiers, we can protect ourselves and our families from adverse air quality.