Indoor aerosol

Indoor aerosol 1

Indoor aerosol

Min ZhongApr. 8th. 2010

ENV 6130

Indoor aerosol 2ENV 6130

1. The importance of study indoor aerosol2. Source of indoor aerosol 3. Particle size4. Transport and behavior5. Case study 5.1 Environmental tobacco smoke 5.2 Cooking aerosol 5.3 Bioaerosol contaminants 5.4 Indoor chemistry as a particle source

Outline

Indoor aerosol 3

What is indoor aerosol

• An indoor aerosol usually refers to that in residences and offices as distinguished from that in industrial workplaces.

• Indoor vs Outdoor• Concentration• Chemical components• Less oxidized than outdoor• Humidity

ENV 6130

Indoor aerosol 4

Why study indoor aerosolWe live indoor

ENV 6130

The national human activity pattern survey 1996

Indoor aerosol 5

Health concerns

ENV 6130

According to the EPA -“Indoor air pollution is one the top 5 most serious environmental problems affecting the health of humans in America”

According to the WHO- 40 percent of all buildings, pose a "serious health hazard” due to indoor air pollution.

Sick Building Syndrome is often linked to unhealthy Indoor Air Quality.

Why study indoor aerosol


• Sick Building Syndrome (SBS)--Acute health and comfort effects experienced by building occupants that are apparently linked to time spent in the building. (EPA)--headache, fatigue, cough, sneezing….--No specific illness identified--Syndrome diminish rapidly when people leave the building•Causes -- Indoor particles, Tobacco smoke, biological contaminants, VOCs…

www.home-air-purifier-expert.com/

Health effect


Health effect cont.

www.home-air-purifier-expert.com/

Infants and young children are the groups shown to be more susceptible to indoor pollutants.

Baby and children generally breathe more rapidly than adults, which increases their exposure to any pollutants in the airA baby's lungs are still developing and therefore are more sensitive than an adult's.


Source of indoor aerosol Outdoor source• Suspended particles: soil, sea salt, road dust, SOA, biological aerosolsIndoor source

Source: U.S. Environmental Protection Agency

Can you give some examples?


Source of indoor aerosol Indoor source• Tobacco combustion • Cooking• Biological contaminants: mold, dust mite• Plants, pets: pollen, spores, bacteria• Building material, especially mineral fibers, asbestos• Combustion appliances: wood stoves, fireplaces• Residues from personal care and household cleaning • Pesticides• Radon decay products• Activities • Indoor chemistry

Indoor aerosol 10

Particle size of indoor aerosol Submicrometer particles: small than 1 um generated mainly from combustion, gas to particle conversion, nucleation process

Supermicrometer particles: larger than 1 um mainly from mechanical process

ENV 6130

The most frequent size in number conc.

Wallace, 2000Abt et. Al 2000

Diameter Source 　　0.01-0.02 gas burners, gas ovens0.1 incense0.05-0.1 frying and boiling0.07-0.085 smoking 0.13-0.25 cooking5-10 walking, moving 　

Indoor aerosol 11

Transport and Behavior• The highest significance processes in affecting

indoor particle include:o Penetration of outdoor particles through open doors, windows as well

as through the building envelopeo Deposition of particles on indoor surfaces.o Resuspension of particles deposited on surfaces.o Removal of particles from an indoor environment by ventilation and

filtrationo Chemical reactions involving vapors and gases leading to particle

generation.o Coagulation

ENV 6130

Indoor aerosol 12

Transport and Behavior cont.

• Penetration of outdoor particles indoors

ENV 6130

Indoor/outdoor pres. diff. (Pa)

Particles penetrated (%)

Size (um)

20.1 52 2

5< 1 540 2

10< 1 585 2

Particle penetration through narrow horizontal slits (0.58×102×433mm)

Mosley et al. 2001

Indoor aerosol 13


Deposition• Particle deposition on indoor surface strongly depends on

particle size. Small: diffusion, large: gravitational sedimentation

• Also depend on the surface area and surface characteristics. Furnished room will have higher deposition rate than bare rooms.

• Depend on the presence and speeds of any air flows in indoor environment. For example, increase the mean air speed from 5 to 19 cm/s, by increasing fan speed, the deposition rate increases by factor of 1.3 to 2.4

ENV 6130

Thatcher et,al. 2002

Indoor aerosol 14


Resuspension of particle• To resuspend the particles, a certain force must be applied to detach

the particles from the surface. • Adhere force d, ∝• Detached force d∝ n

n=2 for vibration, n=3 for air currents• Large particles are being more readily detached than small ones• All the normal activities of the occupants, such as walking, moving

around, children playing, result in an increase in the indoor super micrometer particles.

ENV 6130

Baron and Willeke, 2001

Indoor aerosol 15

Case study

ENV 6130

Environmental tobacco smokeCooking aerosol Bioaerosol contaminantsIndoor chemistry as a particle source

Indoor aerosol 16

Environmental tobacco smoke

• know as second hand smoke• one of the most significant indoor aerosols• small liquid droplets,• Mostly in size range of 0.02 ~2 um • Comprised of low vapor pressure organic compounds

ENV 6130

ETS

Indoor aerosol 17

Contribution of ETS to indoor conc.

PM2.5(ug/m3) in smoking and non smoking homes

ENV 6130

• Most of the studies have indicated an increase in average fine particle levels indoors

From: Harvard Six-City Study


ETS particle size

Size distribution of ETS measured 18 and 300 min after generation

Source: The Handbook of Environmental Chemistry

Indoor aerosol 19

ETS chemical composition• The chemistry of a cigarette smoke is very complex, with a vast

number of elements and compounds generated in particles.

ENV 6130

Organic Inorganic

Organic : 59.9% by mass Species: Cl-, NO2-, NO3-, SO42-,NH4+

Main classes: alkanes, bases, phenols, carboxylic acids, sterenes, aromatics Element: K, Ca, S,Ti, Ba, V, Cr, Mn, Fe, Co, Ni,..

Species: Nicotine, myosmine, nicotyrine, cotiniene, cholesterol, stimaterol

Reported Chemical composition of ETS particles

Kleeman et.al(1999)

Nicotine: make up about 8% of SS smoke particles, a chemical tracer of ETSSS smoke: side stream smoke, classified as a Class A carcinogen by the EPA

Indoor aerosol 20

Case study

ENV 6130


Indoor aerosol 21

Cooking aerosol• One of the most important indoor activity generating fine

particles in doors with non-smokers is cooking• Incomplete combustion of fuel, oil, and food emits various

inorganic and organic compounds.

ENV 6130

Indoor aerosol 22

Cooking aerosol

ENV 6130

S.W. Seea, R. Balasubramanian 2006

Typical temporal profiles of number and mass concentration

Indoor aerosol 23

Size of cooking aerosol

ENV 6130

Size distribution of number concentration during (a) cooking and (b) non-cooking hours, and mass concentration during (c) cooking and (d) non cooking hours. Sample from a Chinese restaurant within the National University of Singapore

S.W. Seea, R. Balasubramanian 2006

Indoor aerosol 24

Chem.comp. of cooking aerosol

ENV 6130

Distribution of PAHs based on the number of rings in the cooking aerosol when different cooking styles applied.

Yi Chen, 2007

The chemistry of a cooking aerosol is very complex, with a lot of organic and inorganic compounds.

Cooking fume is a risk factor of the lung cancer in women non smokers

Indoor aerosol 25

Case study

ENV 6130


Indoor aerosol 26

Bioaerosol contaminants

ENV 6130

‘Bioaerosol contaminants’ refers to a diverse variety of agents from biological sources found in indoor environments. Such as :(1) Viruses and molds(2) bacteria, including endotoxins from bacteria(3) allergens, including house dust mite allergen and allergens from animal(4) fungi which may contain allergens, toxins, and irritants.

Mold ( http://www.mrsars.usda.gov)


Bioaerosol contaminants cont. Always present in the ambient environment

Abundant in soil, rotting vegetation and potted plants

Any building where damp conditions exist will have biological contamination problems

Microbial growth trigger illness, cause asthma / allergies

Indoor aerosol 28

Bioaerosol contaminants cont.

ENV 6130

Release of fungal spores from agar and ceiling tile surfaces at air velocities of 0.3 and 29.1 m/s during 30 min experiments

Microbial growth in a building as a source of bioaerosol

R.L. Gorny et al 2001

Indoor aerosol 29

Indoor chemistry as a source of particles

• Ozone can oxidize terpenes , producing various chemical compounds

• The low volatile compounds can homogenously nucleate or condense onto the surface of preexisting particles to form SOA

ENV 6130

d-limoneneα-pinene

Terpene (C5H8)n

Indoor aerosol 30

Indoor chemistry cont.

• Source of O3 and terpene

ENV 6130

Ozone Terpenes Outdoor to indoor transport Solvents, cleaners, degreasersPhotocopiers, laser printers Odorants in various productsElectrostatic filters Air FreshenersOzone generators Unsealed wood products

Indoor environment, 2003

www.inhabitots.com

Indoor aerosol 31

Indoor chemistry cont.

ENV 6130

Charles J. 1999

Particle concentration in the 0.1-0.2 um size range in Office A (dashed-dotted line, no limonene) and Office B (solid line, with limonene). Right y-axis: Ozone concentrations in Office A (dashed line) and Office B (dotted line)

Discussion: What is the difference between office and residential indoor aerosol ?

Indoor aerosol 32

Review

ENV 6130

The importance of study indoor aerosolSource of indoor aerosol Particle sizeTransport and behaviorEnvironmental tobacco smokeCooking aerosolBioaerosol contaminantsIndoor chemistry as a particle source

Indoor aerosol 33

Thank you!

ENV 6130

Indoor aerosol

Documents

Transcript of Indoor aerosol