A diverse group of citizen scientists monitoring air quality using biomonitors.

Is Air Pollution Silently Harming Your Health? How Citizen Scientists Are Fighting Back

Mira Elwood in Climate & Environment August 2025 • 4 min read.

"Uncover the hidden dangers of nitrogen deposition and how everyday tools can help monitor air quality and protect your well-being."

In today’s world, air pollution is a significant threat to our environment and human health, especially in densely populated areas. An increase in nitrogen deposition, stemming from human activities, is a major concern. While governments and large research bodies monitor air quality, many individuals and communities want a way to take action themselves.

Reactive nitrogen species in the atmosphere, such as NOx and NHx, contribute to the creation of particulate matter and tropospheric ozone, impacting respiratory and heart health. In places like Mexico City, air pollution contributes to thousands of deaths annually. This is where atmospheric biomonitors come in handy.

Biomonitors offer a practical and affordable solution for monitoring air quality. Rather than relying on expensive air quality monitoring networks, widely distributed biological species can provide insights into the levels of nitrogen deposition. These biomonitors include lichens, mosses, and bromeliads, which respond to environmental changes in measurable ways.

What are Atmospheric Biomonitors and How Do They Work?

A diverse group of citizen scientists monitoring air quality using biomonitors.

Atmospheric biomonitors are plant species that can indicate the ecological health of an environment. These organisms respond in measureable ways to atmospheric pollutants. The focus research studied lichens, mosses, and bromeliads around the Valley of Mexico to assess their viability.

Here’s how the biomonitors responded:

Lichens (Anaptychia sp.): Showed significant responses in nitrogen content, C:N ratio, and δ15N values relative to season and site.
Mosses (Grimmia sp. and Fabronia sp.): Displayed a linear response in δ15N to wet deposition, reflecting nitrogen content based on season and site.
Bromeliads (Tillandsia recurvata): Demonstrated a linear response to NOx in nitrogen content, C:N ratio, and δ15N values. High nitrogen disrupted its usability as a biomonitor.

These organisms accumulate pollutants in their tissues. By studying these concentrations, the researchers could then infer the degree of environmental contamination. The study assessed these organisms' nitrogen metabolism parameters, including nitrogen content, carbon-to-nitrogen (C:N) ratio, and nitrogen isotope composition (δ15N).

How Can This Information Be Used?

The study shows how combining various biomonitors can reliably indicate nitrogen deposition. Regular citizens can collect and analyze lichens, mosses, and bromeliads. Doing so will determine the status of atmospheric nitrogenous pollution in areas without formal monitoring networks. This community data can inform public health and environmental policies, leading to more effective pollution control measures and improving overall environmental quality.

About this Article -

This article was crafted using a human-AI hybrid and collaborative approach. AI assisted our team with initial drafting, research insights, identifying key questions, and image generation. Our human editors guided topic selection, defined the angle, structured the content, ensured factual accuracy and relevance, refined the tone, and conducted thorough editing to deliver helpful, high-quality information.See our About page for more information.

This article is based on research published under:

DOI-LINK: 10.1038/s41598-018-32000-5, Alternate LINK

Title: Characterization Of Nitrogen Deposition In A Megalopolis By Means Of Atmospheric Biomonitors

Subject: Multidisciplinary

Journal: Scientific Reports

Publisher: Springer Science and Business Media LLC

Authors: Edison A. Díaz-Álvarez, Erick De La Barrera

Published: 2018-09-11

Everything You Need To Know

What is nitrogen deposition, and why should I be concerned about it?

Nitrogen deposition refers to the process where reactive nitrogen compounds, produced largely by human activities, are deposited from the atmosphere onto land and water surfaces. This includes various forms of nitrogen, such as NOx and NHx. Excessive nitrogen deposition can lead to several environmental and health problems, including the creation of particulate matter, tropospheric ozone, and the disruption of ecosystem balance. In affected areas, reactive nitrogen can affect both respiratory and heart health.

What exactly are atmospheric biomonitors, and how do they help in assessing air quality?

Atmospheric biomonitors are plant species, like lichens (Anaptychia sp.), mosses (Grimmia sp. and Fabronia sp.), and bromeliads (Tillandsia recurvata), that respond measurably to changes in air quality. They accumulate pollutants in their tissues. By analyzing the nitrogen content, carbon-to-nitrogen (C:N) ratio, and nitrogen isotope composition (δ15N) in these organisms, scientists and citizen scientists can infer the degree of atmospheric nitrogen pollution in a specific area.

How do lichens, mosses, and bromeliads individually respond to varying levels of nitrogen deposition?

Lichens (Anaptychia sp.) respond to nitrogen deposition by changing their nitrogen content, C:N ratio, and δ15N values based on seasonal and site-specific conditions. Mosses (Grimmia sp. and Fabronia sp.) show a linear relationship between their δ15N values and wet nitrogen deposition. Bromeliads (Tillandsia recurvata) display a linear response in their nitrogen content, C:N ratio, and δ15N values to NOx levels, but very high nitrogen levels can make them unreliable as biomonitors. Therefore, the health and composition of these species provides insight into air quality.

As a citizen scientist, how can I contribute to monitoring nitrogen pollution using these biomonitors?

Citizen scientists can collect lichens, mosses, and bromeliads from their local environments and send them to labs for analysis of nitrogen content, C:N ratio, and δ15N values. This data, when combined with data from other community members, can provide a comprehensive picture of nitrogen pollution levels across a wider area than traditional monitoring networks cover. These findings can then inform public health initiatives and environmental policies, potentially leading to better pollution control measures and improved environmental quality. This allows regular citizens to engage in environmental protection.

Are there limitations to using lichens, mosses, and bromeliads as air quality indicators, and what other factors should be considered for a more complete assessment?

While lichens, mosses and bromeliads are very useful, they might not capture the full spectrum of pollutants present in the atmosphere. Other pollutants, like sulfur dioxide and heavy metals, also pose significant risks to both human health and the environment. Future research could explore the use of additional biomonitor species or combine biomonitoring with other monitoring techniques to gain a more comprehensive assessment of overall air quality. This would provide a more complete picture of the various pollutants affecting the air we breathe.