Air Pollution in the Food Industry - Practice Flashcards

Flashcards covering key air quality indicators, abatement techniques, and safety standards in the food industry based on lecture material by Dr. Eileen B. Cayetano.

How is "Air Quality" defined in the lecture notes?

Air Quality refers to the degree to which ambient air is clean, unpolluted, and safe for humans, animals, vegetation, and the surrounding environment to breathe.

According to NOAA data presented in the lecture, what are the top two gases by volume fraction in unpolluted clean dry air?

Nitrogen ($78.084\%$ or $780,840\,\text{ppm}$) and Oxygen ($20.946\%$ or $209,460\,\text{ppm}$).

What are the eight key indicators of air quality listed in the lecture?

1) Air Quality Index (AQI), 2) Fine Particulate Matter ($\text{PM}_{2.5}$), 3) Coarse Particulate Matter ($\text{PM}_{10}$), 4) Ground-Level Ozone ($\text{O}_3$), 5) Nitrogen Dioxide ($\text{NO}_2$), 6) Sulfur Dioxide ($\text{SO}_2$), 7) Carbon Monoxide ($\text{CO}$), and 8) Volatile Organic Compounds (VOCs).

What scale does the US EPA Air Quality Index (AQI) use, and what threshold indicates unhealthy air conditions?

The AQI converts pollutant concentrations into a standardized scale from $0\text{ to }500$. Readings below $100$ are generally acceptable, while readings above $100$ indicate unhealthy conditions.

What are the four primary air quality abatement strategies utilized in food manufacturing?

1) HVAC and Filtration Systems, 2) Positive Air Pressure and Zoning, 3) Active Air Disinfection, and 4) Dust Extraction at the Source.

Based on MERV rating and efficiency, what are the four main types of air filtration systems described in HVAC setups?

1) Prefilters (MERV 8–11), 2) Secondary/Medium-Efficiency Filters (MERV 13–16), 3) HEPA Filters (captures $\ge 99.97\%$ of particles down to $0.3\,\mu\text{m}$), and 4) Activated Carbon (Molecular) Filters.

How does positive air pressure function as an environmental barrier in cleanroom areas?

Positive air pressure maintains a higher atmospheric pressure inside the cleanroom by supplying more filtered air in than is exhausted out. When doors or pass-throughs open, air flows outward, preventing external dirty air, pathogens, and allergens from entering.

What are the three zones established in Hygienic Zoning and their associated risk levels?

1) Basic / Low-Care Zone (Low Risk - storage, receiving, non-product areas), 2) Medium-Care Zone (Medium Risk - raw processing, washing, cooking preparation), and 3) High-Care / High-Risk Zone (High Risk - post-kill step handling, ready-to-eat exposure, packaging).

How does active air disinfection differ from traditional passive air disinfection systems?

Traditional passive systems rely on drawing air through duct filters or UV light chambers (waiting for dirty air to pass through), whereas active systems continuously send purifying agents directly into the room environment to neutralize contaminants at the source in real time.

What is the process and mechanism of Photocatalytic Oxidation (PCO) in active air disinfection?

UV light activates a metal catalyst (such as Titanium Dioxide, $\text{TiO}_2$), generating oxidizers like hydroxyl radicals ($\cdot\text{OH}$) and hydrogen peroxide ($\text{H}_2\text{O}_2$) vapor, which destroy VOCs and biological pollutants, converting them into clean air ($\text{H}_2\text{O}$ and $\text{CO}_2$).

How does Bipolar Ionization (Cold Plasma) technology clear pollutants from indoor air?

A bipolar ionizer creates positive and negative ions ($+\text{ and }-$) that attach to and cluster around airborne particles/pathogens, causing them to clump into heavier particles that settle out of the air rapidly or are captured by filter units.

Why are gaseous ozone ($\text{O}_3$) or chlorine dioxide ($\text{ClO}_2$) sanitization treatments scheduled off-shift?

Gaseous sanitization generates high concentrations of gas to penetrate hard-to-reach niches and room volumes. Off-shift scheduling ensures worker absence during high concentration generation, and the gas is scrubbed out before safe re-entry.

What is dust extraction at the source (source capture) in food processing?

It is an engineering control that uses targeted high-velocity vacuum hoods or local exhaust ventilation (LEV) mounted directly over dusty equipment to capture airborne dust at the exact point of creation before it can disperse into the plant air.

What are the five steps involved in a source dust extraction system?

1) Dust Generation & Capture Hood, 2) High-velocity Ductwork Transport, 3) Cyclone Pre-Separation (uses centrifugal force to remove larger particles), 4) Pulse-Jet Cartridge Filter (high-efficiency MERV 16/HEPA filters capture fine dust), and 5) Clean Air Exhaust & Recirculation.

What is Fine Particulate Matter ($\text{PM}_{2.5}$) and how do its primary and secondary sources differ?

$\text{PM}_{2.5}$ consists of airborne particles measuring $2.5\,\mu\text{m}$ or less in diameter. Primary sources directly emit particles (e.g., diesel exhaust, industrial stacks), while secondary sources are formed in the atmosphere through chemical reactions of precursor gases like $\text{SO}_2$ and $\text{NO}_x$.

Why does Fine Particulate Matter ($\text{PM}_{2.5}$) pose higher direct health risks than larger particles?

Because of its microscopic size, $\text{PM}_{2.5}$ bypasses natural upper respiratory defenses (nose and throat), penetrates deep into lung alveoli, and enters the bloodstream, causing elevated risks for asthma attacks, cardiovascular disease, stroke, and systemic inflammation.

What is Coarse Particulate Matter ($\text{PM}_{10-2.5}$) and how is it generated?

Coarse particulate matter consists of inhalable airborne particles measuring between $2.5\,\mu\text{m}$ and $10\,\mu\text{m}$ in diameter. It is generated primarily through mechanical actions like crushing, grinding, abrasion, and soil suspension.

What are three distinctive characteristics of coarse food dust ($\text{PM}_{10}$)?

1) Biological composition (composed of proteins, starches, cellulose, mold spores, and sugars), 2) Rapid settling rate (heavy particles settle quickly onto floors and equipment), and 3) Combustibility (concentrated airborne clouds can cause industrial dust explosions).

How is outdoor ground-level ozone ($\text{O}_3$) formed?

Ground-level ozone is a secondary air pollutant formed when nitrogen oxides ($\text{NO}_x$) and volatile organic compounds (VOCs) react chemically in the presence of sunlight.

What is the key difference between stratospheric ozone and ground-level ozone?

Stratospheric ozone ($10\text{--}50\,\text{km}$ altitude) is beneficial because it shields Earth from harmful UV radiation. Ground-level tropospheric ozone ($0\text{--}10\,\text{km}$) is a harmful pollutant causing human respiratory damage and crop damage.

How does elevated outdoor ground-level ozone affect raw agricultural crops?

It damages plant tissues (causing cell breakdown and visible leaf injury), inhibits photosynthesis (slowing growth), and reduces overall crop yield quantity and quality.

What strict regulatory ambient threshold range is required by OSHA and FDA for indoor ozone exposure?

Regulations require worker-exposed ambient ozone air to remain below strict safety limits, typically $0.05\,\text{ppm}\text{ to }0.1\,\text{ppm}$ time-weighted average.

What quality degradation occurs when oil- or fat-containing foods are exposed to excessive ambient ozone?

Excessive ozone oxidizes fats and oils, leading to oxidative rancidity, foul odors, degraded flavors, loss of nutrients, and shortened product shelf life.

What is Nitrogen Dioxide ($\text{NO}_2$) and what primarily generates it?

Nitrogen Dioxide is a foul-smelling, highly reactive, reddish-brown gas formed as a byproduct of high-temperature fuel combustion where atmospheric nitrogen and oxygen react under intense heat.

What are internal and external sources of Nitrogen Dioxide ($\text{NO}_2$) in food facilities?

Internal sources include gas-fired boilers, direct-fired ovens/dryers, and backup diesel generators. External sources include heavy diesel trucks and transport refrigeration units idling at loading docks.

What are the occupational exposure limits for Nitrogen Dioxide ($\text{NO}_2$) according to OSHA and ACGIH?

OSHA set an exposure limit of $5\,\text{ppm}$, while ACGIH recommended a lower threshold of $0.2\,\text{ppm}$.

What dual role does Sulfur Dioxide ($\text{SO}_2$) play in the food industry?

It acts as an unwanted atmospheric pollutant generated by fuel combustion and transport logistics, and as a controlled indoor chemical agent intentionally applied for food preservation (e.g., wine, juice, dried fruit).

What health risks do plant operators face when exposed to low indoor concentrations ($1\text{--}5\,\text{ppm}$) of Sulfur Dioxide ($\text{SO}_2$)?

Low concentrations cause coughing, throat irritation, and chest tightness, while localized spikes trigger severe bronchospasms in workers with asthma or preexisting conditions.

How does airborne Sulfur Dioxide ($\text{SO}_2$) damage facility infrastructure and HVAC equipment?

Airborne $\text{SO}_2$ reacts with high humidity to form sulfurous and sulfuric acids, causing acidic air conversion that corrodes exposed metal contacts, electrical panels, ductwork, and cooling coils over time.

How is Carbon Monoxide ($\text{CO}$) formed and what are its physiological dangers?

Carbon Monoxide is a poisonous, colorless, odorless, and tasteless gas formed by incomplete fuel combustion. It binds to hemoglobin $200\times$ more strongly than oxygen ($\text{O}_2$), forming carboxyhemoglobin ($\text{COHb}$) and depriving body tissues of oxygen. The OSHA 8-hour PEL is $50\,\text{ppm}$.

How is Carbon Monoxide ($\text{CO}$) used as a metric in Modified Atmosphere Packaging (MAP)?

Ultra-low concentrations (approximately $0.4\%$) of $\text{CO}$ are used to bind with myoglobin to form carboxymyoglobin, maintaining a stable, fresh cherry-red color in raw beef and pork.

What are Volatile Organic Compounds (VOCs)?

VOCs are carbon-based chemicals that evaporate easily into the air at room temperature. In food plants, they comprise natural organic vapors (food aromas, alcohols, terpenes) and synthetic chemical fumes (cleansers, solvents, packaging off-gases).

How does VOC tracking assist in early detection of product spoilage and process quality control?

Specific VOC emission profiles change before visual mold appears on stock, serving as an early alert for decaying stock. Tracking VOCs also ensures consistent roasting/cooking, prevents flavor cross-contamination, and detects packaging chemical migration.