Embedded Files
§§§§§§§§§§§§§§§§§§§§§
https://www.transportpolicy.net/standard/mexico-air-quality-standards/
WHO global air quality guidelines: particulate matter (PM2.5 and PM10), ozone, nitrogen dioxide, sulfur dioxide and carbon monoxide
What are the Air Quality Standards for PM?
Air pollution – How to convert between mg/m3, µg/m3 and ppm, ppb
¢ƒ…
Why is particulate matter dangerous?
Particulate matter is linked to cardiovascular and respiratory diseases such as asthma, bronchitis, emphysema, and even cancer. It has been found that the smaller the particle, the higher the health risk because of its ability to penetrate deeper into the body. Generally, PM10 irritates the eyes, nose, and throat, while PM2.5 is able to penetrate deep into the respiratory and circulatory systems, thus causing damage to the lungs, heart, and brain.
∫∫∫
The impact of PM2.5 on the human respiratory system
∫∫∫
Most studies indicate PM2.5 at or below 12 μg/m3 is considered healthy with little to no risk from exposure. If the level goes to or above 35 μg/m3 during a 24-hour period, the air is considered unhealthy and can cause issues for people with existing breathing issues such as asthma. Prolonged exposure to levels above 50 μg/m3 can lead to serious health issues and premature mortality.
∫∫∫
The negative health effects associated with exposure to particulate matter are significant. A 2021 Harvard study found that particulate matter air pollution from burning fossil fuels was responsible for 10.2 million global excess deaths in 2012. The methods used in the study allowed researchers to link premature deaths from PM2.5 exposure to fossil fuel combustion, attributing this as the cause for 1 in 5 premature deaths worldwide. The same study estimates that 350,000 premature deaths associated with fossil fuel pollution occurred in the United States in 2018.
—— An alarming 91% of the world’s population lives in areas where PM2.5 levels exceed the WHO’s benchmarks for healthy air. Approximately 4 billion people live in areas where the mean annual concentrations of PM2.5 do not meet the WHO’s least stringent target of 35 µg/m³.
¢ƒ image below
The WHO states that long-term exposure for those living above an annual average PM2.5 concentration of 10 µg/m³ has a higher risk of death from lung cancer and cardiopulmonary issues. Based on this criterion, over 90% of the global population is exposed to unhealthy air.
∫∫∫
Particulate Matter (PM) Basics @ EPA
Air Now display for CdMx nowcast
--- en este último sitio se puede seleccionar en el mapa de CdMx la concentración (en tiempo real) tanto de Ozono como de Partículas--
Face Masks
ASTM — Mask protection standards & Medical Face Mask info. for use
4. Delta P (Pressure Differential): Delta P measures the air flow resistance of the medical mask and is an objective measure of breathability. The Delta P is measured in units of mm H2O/cm2 and the lower the value the more breathable the mask feels. The ASTM standard requires that masks have a Delta P of less than 6.0 for moderate and high barrier masks, whereas low barrier masks must have a Delta P of less than 5.0.
§§§§§§§§§§§§§§§§§§§§§§
Open-Mask-Lab: A virtual open Lab for sharing face masks test design, analysis & calibration
The Differential Pressure or Breathability test is the direct measure of the respiratory resistance provided by the mask, evaluated as pressure drop at fixed flow, and it is thus correlated to the effort required by the wearer in order to breath with conventional inhalation/exhalation rates. Taking advantage of the uniformity of the surgical mask, the tests are executed on a representative section, a circular sample of 25 mm of diameter (i.e. 4.91 cm2 of area), in which the pressure drop need to be measured when impacted by 8 L/min air flow
§§§§§§§§§§§§§§§§§§§§§§
A Modified Method for Measuring Pressure Drop in Non-medical Face Masks with Automated Data Acquisition and Analysis
—- The velocity used by the CDC was determined by dividing the flow rate by the area of the respirator (A3M-1860). Here A3M-1860 is expressed in cm2 and 16.67 is the conversion factor required to convert L/minute to cm3/s. The corresponding flow rate, Q, required in our pressure rig that uses a 2.5 cm cross sectional coupon that would give the same amount of velocity is then given by ….
§§§§§§§§§§§§§§§§§§§§§§
PRESSURE DROP OF FILTERING FACE-PIECE RESPIRATORS:
HOW LOW SHOULD WE GO?
In-line pressure transducer measurements of mean Rfilter across PRs with nominal Rfilter of 29.4 Pa, 58.8 Pa and 88.2 Pa (measured at 85 l/min constant airflow) were obtained during nasal and oral breathing at sedentary and low-moderate work rates for 10 subjects.
§§§§§§§§§§§§§§§§§§§§§§
Page updated
Google Sites
Report abuse