Wondering What Is Normal Air Quality? Explore baselines, pollutants, and how we measure air quality.

There's more to air quality than just one pollutant—it's about everything in the environment. What is normal air quality? It refers to the baseline concentrations that shape what we breathe. Any air quality assessment needs this baseline, but it's not easy. The process involves gathering data from monitoring stations or, if they're not available, similar regions with comparable weather and pollution levels. Natural sources also play a big role in defining what 'normal' air is.

There are different methods for determining baseline concentrations depending on how detailed the assessment is. If you're doing a simple study, you might use the highest recorded concentration. To capture daily variations, more complex assessments use percentiles. Besides air pollution, future emissions or decommissioning of facilities will change what we call 'normal.'

Here's the twist: What's normal air quality depends on location, activities, and environment. "Normal" might take years of historical data and careful professional judgment. Without it, air quality modelling would be inaccurate, and regulatory decisions could go wrong. These invisible factors help paint a bigger picture of how pollution affects us.

Are you ready to learn more? There are several reasons why anyone might be interested in reading about what is normal air quality: 

What's in your air?

You breathe it every day, but do you know what's really in it? To get the full picture of what you're breathing, you need to know baseline air quality.

Air pollution is everywhere, even when it seems 'normal.' What we think is 'normal' air may still contain harmful pollutants from natural and human sources.

'Normal' isn't what you think: Discover how your air quality changes constantly. 'Normal' air quality changes over time and space, especially as emissions from different sources rise and fall.

Local air matters more than you think: Your neighborhood's air might be different from the city's. Even within small regions, air quality varies a lot based on baseline concentrations.

The air quality in your environment could be silently affecting your health. You can learn how your air is affecting your health without even realizing it by diving into baseline concentrations.

Find out how new sources and shutdowns are changing what's normal. The air you breathe changes as factories, traffic, and other sources emit emissions.

Have you ever wondered if your air is really clean? You can find out now. Here's how to tell if your local air meets environmental standards.

Learn how to challenge air quality myths. Air quality isn't as simple as people think. This text shows how local and regional pollutants interact.

You'll never look at air quality reports the same way again. Air quality reports only tell part of the story once you understand baseline data.

Learn about air pollution's hidden sources to protect your family. Readers will gain insight into how both natural and human-made pollutants impact 'normal' air, so they can make informed health choices.

Background Concentrations and Dispersion Modelling in British Columbia

The baseline includes contributions from all sources except the one being modelled in your dispersion study, so understanding the overall air quality impact isn't just about the emissions from a specific source. Monitoring data or modelling can be used to determine a baseline for accurate assessment.

What are your air pollution risks?

Monitoring data can be used to establish what is normal air quality if they're available. You can use data from a similar location with similar weather and air quality. Choosing a baseline should reflect the purpose of the modeling assessment, like determining compliance or estimating risks.

Different methods are recommended to select the baseline concentration based on factors like pollutant type and averaging period. In Level 1 (simple) Assessments, the maximum measured concentration is usually used as a baseline, while in higher-level assessments, percentiles of daily maximum values are allowed.

A screening model can help determine the contribution of emissions from other sources when including the baseline in the modeling. Changes in emissions, like those associated with new sources or decommissioning old ones, should also be considered if they impact air quality.

It's essential to establish the baseline concentration accurately for meaningful air quality modelling assessments, and there are different methods depending on the data available.

Setting up Alberta's industrial and natural emission baselines

For accurate air quality modelling, you need a baseline. Emissions from both natural and human-made sources are included in baseline air quality, and so professional judgment is needed when picking a baseline value to determine what is normal air quality.

To determine baseline values, factors like the nature of missing emissions and similarity to the project site's conditions need to be taken into account. To isolate the impact of heavily industrialized areas, you might choose a station that captures traffic and residential emissions but not industrial emissions.

natural sources of air pollution

Baseline concentrations:

• Verify and quality-control monitoring data, preferably hourly.
• Average three years of hourly ambient data, ensuring at least 75% completeness.
• As a baseline, use the 99.9th percentile of non-blank hourly values.

To account for local variability in refined assessments, use the 90th percentile. Calculate hourly and longer-average baselines based three years of data. Next, average the top-ranked one-hour values from each year and take the maximum for the longer averages.

For substances like TSP without monitoring, scale PM10 data by two to get baseline values. Use representative baseline values based on the literature if there are no suitable monitoring data.

It's important to choose appropriate baseline values for accurate air quality assessments, so both natural and human-made emissions are taken into account.

Refining Saskatchewan Air Quality Dispersion Model Output and Baselines

Baseline concentrations must be considered before comparing modelling results. Model predictions need to include existing air quality with nearby and long-range sources.

Often, "baseline" and "background" are used interchangeably, but they're different. Natural and anthropogenic sources contribute to background concentrations, which are consistent over a wide area. Typically covering a smaller area, baseline concentrations include background levels and local activity.

Air quality in cities and rural areas

Background monitors provide data on regional background concentrations in rural areas. For each contaminant, a single value is often selected conservatively and applied uniformly.

In urban areas with a lot of minor sources, regional baseline concentrations may need to be refined. Baseline values can be derived from nearby sites.

To figure out baseline concentrations:

• Monitoring data should be validated and quality-controlled, preferably hourly and continuous.
• Make sure the three years of ambient data chosen are at least 75% complete.
• Use the 90th percentile of non-blank ambient data for screening.
• Calculate the maximum average from the reduced data set for longer averaging periods.

Baseline concentrations should be justified and supported by data in modelling reports. Predefined baseline concentrations based on land area can be used if monitoring data aren't available. Air quality standards and objectives can't be measured without baseline concentrations.

What is normal air quality in Manitoba

Air quality should be considered when assessing a source's impact. Both screening and refined air dispersion modelling rely on these background concentrations.

Use data from representative air monitoring stations in the study area, making sure it meets quality assurance criteria. Considering other sources' contributions to background concentrations is important if significant impacts are expected.

After consulting with relevant authorities, you can consider data from similar areas if local monitoring data aren't available. On-site monitoring may be required for larger projects with potential impacts and no representative data, typically for one year.

Expertise in Air Quality Dispersion Modelling

Is your business looking for a streamlined solution to ensure compliance with air quality regulations or preparation for emergencies? For projects in Western Canada, Calvin Consulting Group Ltd. brings over 95 years of combined experience in air quality dispersion modeling.

Both natural and human-made emissions need to be accurately assessed to protect the environment and your business. For regulatory approvals, we provide detailed reports that help you ensure your project is on track. From air quality monitoring to dispersion models using advanced tools like AERMOD or CALPUFF, we've got you covered.

Put our experience to work for you instead of trying to figure everything out on your own.  Having worked with top Canadian agencies like Alberta Environment and Environment Canada, we know how to deliver reliable, fast, and effective results.

Get started with your air quality modelling assessment by contacting Barry at Calvin Consulting. 

Let us help you meet regulatory requirements with precision and ease.

​Clean air is our Passion...Regulatory Compliance is our Business.

Our goal is to understand baseline air quality by assessing both natural and human-made emissions.

This page explains how to determine what a "normal" level of air quality looks like before introducing new emissions, which aligns closely with the concept of establishing what normal air quality is in different places.

Do you have concerns about air pollution in your area??

Perhaps modelling air pollution will provide the answers to your question.

That is what I do on a full-time basis.  Find out if it is necessary for your project.

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